P.A. Kelly 1984 Journal While I was checking traps I also clumped into one of the Parks engineers - he said there definitely were rats in the buildings and in the roof of the cell block. So there were at least 16 Peromyscus maniculatus on the island, and I had 64% trap success. Longworths are difficult to transport while assembled but I solved my problem by putting empty traps (9) into my backpack. Then I tightened up the other 16, labelled them and taped them shut. Those 16 fitted neatly into one of Bob Jones' new canvas shoulder bags. We got back to Berkeley at 3.30 pm and I transferred all 16 mice to individual holding cages, with bedding, grain, rat chow and water, and left them in my office for the moment.